Spatiotemporal assessment of β-arrestin-centred “signalosomes” – the impact of effector binding on GPCR functional selectivity.

G protein-coupled receptors (GPCRs) fulfil important roles in most physiological processes. Activation of GPCRs via agonist binding prompts conformational changes that lead to their association with signalling components at the plasma membrane. While G proteins induce second messenger signalling, β-arrestins also bind GPCRs directly and change their conformation according to the receptor’s activation and phosphorylation state. Here, β-arrestins facilitate GPCR internalisation to further support signalling from intracellular compartments. I hypothesise that this signalling is controlled by the composition and localisation of functional GPCR-β-arrestin-effector complexes. Due to a lack of unbiased tools and focus on individual receptors, current research addressing these processes fails to portrait commonalities between GPCRs. Hence, I aim to systematically monitor and compare the dynamics of twelve GPCR-β-arrestin-effector complexes to assess how they are influenced by subcellular trafficking. This project will establish novel in cellulo and bioinformatic methodologies to construct a subcellular trafficking and interaction map between GPCRs/arrestins and their key effectors with high spatial and kinetic resolution. Via this contextualisation of protein-protein interactions, β-arrestin conformations and downstream signalling with their subcellular localisation, I aim to offer an alternative to conventional drug discovery through location-specific targeting, while discovering how GPCRs “program” β-arrestins to fulfil specific cellular functions.